I had a Special Precision 5 from Squier. The general quality of the instrument was good. The bass I had wasn't pro quality for 3 reasons:
1) The pickups were apparently not designed for 5 strings. The strings looked too wide for the pickup and the outer strings, particularly the B string, lacked clarity. The pole pieces were not visible due to a pickup cover/casing, so I can only speculate it was a 4-string Jazz pickup used as a cost saving measure.
2) The treble side of the fret wires were sharp.
3) When playing a fretted string, buzz was audible from between the nut and the fretting finger.
With all that said, I think it is a good bass to learn on or to upgrade. I own 3 other Squiers, all of which are outstanding in quality and performance. In my opinion, that model (Special Precision 5) had some inherent weaknesses, but could've been a cool custom project. If those things don't bother you, go for it if the price is right!